Bearing cup and retainer strap for universal joint

ABSTRACT

A universal joint assembly which prevents the bearing cups from rotating relative to the end yokes during use. In a first embodiment, the arms of a half round end yoke are formed having integral tabs which extend over the recessed areas of the associated bearing cups. The tabs cooperate with the shoulders to prevent the bearing cups from rotating relative to the end yoke. In a second embodiment of the half round end yoke, retainer straps extending about the outer circumferential surface of the bearing cups are provided with integral flanges. The retainer strap flanges cooperate with the bearing cup shoulders in the same manner as the tabs to prevent relative rotation. In a third embodiment, the bearing cups are disposed in openings formed in the arms of a full round end yoke. A retainer strap has end portions which are formed at a slight angle relative to the central portion. In a fourth embodiment, the retainer straps are secured to the full round end yoke by spring clips.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of Ser. No. 07/696,229 filedMay 6, 1991, now U.S. Pat. No. 5,376,051 issued Dec. 27, 1994.

BACKGROUND OF THE INVENTION

This invention relates in general to universal joints and in particularto an improved structure for restraining the bearing cups mounted on auniversal joint cross from rotating relative to an end yoke connectedthereto during use.

Universal joints are well known devices which provide a drivingconnection between two members adapted to rotate about non-aligned axesof rotation. Universal joints of this type are widely used betweenrotatable drive shafts in vehicle drive train systems. Typically, suchuniversal joints include a cross having a central body portion with fourtrunnions extending outwardly therefrom. The trunnions are oriented in asingle plane and extend at right angles relative to one another. Abearing cup is mounted on the end of each of the trunnions. Needlebearings or similar means are provided between each of the trunnions andits associated bearing cup to permit the bearing cup to rotate relativeto the trunnion. One pair of opposed bearing cups is connected to afirst end yoke secured to the first drive shaft, while the other pair ofopposed bearing cups is connected to a second end yoke secured to thesecond drive shaft.

When the axes of rotation of the two drive shafts are not co-axiallyaligned during operation, the bearing cups rotate relative to thetrunnions in an oscillating fashion so as to permit the drivingconnection. It is desirable that the bearing cups be fixed in positionrelative to the end yokes connected thereto such that no relativerotation occurs therebetween. Otherwise, wear will occur in the endyokes and the outer surfaces of the bearing cups, causing prematurefailure of the universal joint. Many structures are known for preventingrelative rotation from occurring between the bearing cups and the endyokes. For example, it is known to weld plates onto the end surfaces ofthe bearing cups and to bolt such plates to the end yoke. However, thisstructure, as well as other anti-rotation structures known in the art,requires extra parts and additional labor to install, thus increasingthe cost and complexity of the universal joint. Furthermore, such anarrangement does not readily accommodate stack-up tolerances caused bythe assembly of the various components. Accordingly, it would bedesirable to provide an improved universal point with an anti-rotationstructure which is simple and inexpensive to construct and assemble, andwhich readily accommodates such stack-up tolerances.

SUMMARY OF THE INVENTION

This invention relates to several improvements in a universal jointassembly which prevent the bearing cups from rotating relative to theend yokes during use. Each of the bearing cups includes a pair ofrecessed areas formed on the opposite sides of an end surface. Each ofthe recessed areas defines a chord-like shoulder. The bearing cups maybe connected to either a half round end yoke or a full round end yoke.In a first embodiment of the half round end yoke, the arms of the endyoke are formed having integral tabs which extend over the recessedareas of the associated bearing cups. The tabs cooperate with theshoulders to prevent the bearing cups from rotating relative to the endyoke. In a second embodiment of the half round end yoke, retainer strapsextending about the outer circumferential surface of the bearing cupsare provided with integral flanges. The retainer strap flanges cooperatewith the bearing cup shoulders in the same manner as the tabs to preventrelative rotation.

In the full round end yoke embodiments, a retainer strap is providedwhich extends across the end surface of each of the bearing cups. Theretainer straps are formed having stepped portions which extend into therecessed areas of the bearing cups to prevent relative rotation. Thelocating surfaces on the arms and the bearing cups may or may not beco-planar. In a first embodiment of the full round yoke, the endportions of the straps are formed at a slight angle relative to thecentral portions. The end portions function like springs to take up anylooseness caused by stack-up tolerances and to pre-load the threadedfasteners securing the retainer straps to the arms. In a secondembodiment of the full round end yoke, the retainer straps are securedto the yoke by spring clips which provide a similar resilient function.

Various objects and advantages of this invention will become apparent tothose skilled in the art from the following detailed description of thepreferred embodiments, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a first embodiment of auniversal joint assembly adapted for use with a half round end yoke inaccordance with this invention.

FIG. 2 is a plan view of the universal joint assembly illustrated inFIG. 1 shown assembled.

FIG. 3 is an exploded perspective view of a second embodiment of auniversal joint assembly adapted for use with a half round end yoke inaccordance with this invention.

FIG. 4 is a plan view of the universal joint assembly illustrated inFIG. 3 shown assembled.

FIG. 5 is a plan view of a third embodiment of a universal jointassembly adapted for use with a full round end yoke in accordance withthis invention.

FIG. 6 is a sectional elevation view of the universal joint assemblyillustrated in FIG. 5.

FIG. 7 is a side elevational view of the retainer strap illustrated inFIGS. 5 and 6 shown in an unstressed condition.

FIG. 8 is a sectional elevational view of a fourth embodiment of auniversal joint assembly adapted for use with a full round end yoke inaccordance with this invention.

FIG. 9 is a side elevational view of the spring washer illustrated inFIG. 8 shown in an unstressed condition.

FIG. 10 is a plan view of a fifth embodiment of a universal jointassembly adapted for use with a full round end yoke in accordance withthis invention.

FIG. 11 is a sectional elevation view of the universal joint assemblyillustrated in FIG. 10.

FIG. 12 is a tom plan view of a modified version of a retainer clipadapted for use in the universal joint assembly of FIGS. 10 and 11.

FIG. 13 is a sectional elevational view of the modified retainer cliptaken along line 13--13 of FIG. 12.

FIG. 14 is a sectional elevational view of the modified retainer cliptaken along line 14--14 of FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, there is illustrated in FIG. 1 anexploded perspective view of a first embodiment of a universal jointassembly, indicated generally at 10, in accordance with this invention.The assembly 10 includes a conventional cross member 11 having fourtrunnions extending radially outwardly in a common plane at right anglesrelative to one another. A bearing cup, indicated generally at 12, ismounted on the end of each of the trunnions. Needle bearings (not shown)or similar bearing means are provided between each of the bearing cups12 and its associated trunnion to permit relative rotation therebetween.

Each of the bearing cups 12 is formed generally in the shape of a hollowcylinder having an outer circumferential surface 13 and a closed endsurface 14. Two recessed areas 15 are formed in each of the end surfaces14. The recessed areas 15 are defined by parallel chord lines extendingto the circumferential edges of the bearing cup 12, although they may bedefined by curved lines as well. Shoulders 15a are defined betweenrecessed areas 15 and the end surfaces 14 of the bearing cups 12.

The illustrated assembly 10 further includes a first embodiment of ahalf round end yoke 20. The end yoke 20 includes a pair of arms 21 and22 having semi-cylindrical recesses 21a and 22a formed therein. A tab 23is formed integrally with each of the yoke arms 21 and 22. The tabs 23extend over the ends of the respective semi-cylindrical recesses 21a and21b. When the cross 11 is assembled to the end yoke 20, two opposedbearing cups 12 are received in the recesses 21a and 22a, as shown inFIG. 2. The tabs 23 extend over one of the recessed areas 15 formed inthe end surfaces 14 of the bearing cups 12. The tabs 23 engage the oneof the shoulders 15a formed on such end surfaces 14 so as to preventrotation of the bearing cups 12 relative to the associated arms 21 and22 of the end yoke 20. The tabs 23 may be formed having generally flatend surfaces for contacting the shoulders 15a.

Means are provided for retaining the bearing cups 12 within thesemi-cylindrical recesses 21a and 22a of the end yoke 20. As shown inFIGS. 1 and 2, such means includes a pair of retainer straps 24. Thecentral portions of the retainer straps 24 extend around respectiveportions of the outer circumferential surfaces 13 of the bearing cups12. The end portions of the retainer straps 24 are secured to the arms21 and 22 by threaded fasteners 25. Although there is some frictionalengagement between the bearing cups 12 and the arms 21 and 22, suchfrictional engagement is not, of itself, sufficient to prevent relativerotation therebetween under all conditions. Thus, the cooperation of thetabs 23 with the shoulders 15a is provided to prevent such relativerotation.

Referring now to FIGS. 3 and 4, there is illustrated a second embodimentof a universal joint assembly, indicated generally at 30, in accordancewith this invention. The assembly 30 includes a conventional crossmember 11 having bearing cups 12 mounted thereon, as described above inconnection with FIGS. 1 and 2. The assembly 30 further includes a secondembodiment of a half round end yoke 31. The end yoke 31 includes a pairof arms 32 and 33 having semi-cylindrical recesses 32a and 33a formedtherein. When the cross 11 is assembled to the end yoke 31, two opposedbearing cups 12 are received in the recesses 32a and 33a, as shown inFIG. 4.

Means are provided for retaining the bearing cups 12 within thesemi-cylindrical recesses 32a and 33a of the end yoke 31. As shown inFIGS. 3 and 4, such means includes a pair of retainer straps 34. Thecentral portions of the retainer straps 34 are curved and extend aroundrespective portions of the outer circumferential surfaces 13 of thebearing cups 12. The end portions of the retainer straps 34 are securedto the arms 32 and 33 by threaded fasteners 35. However, unlike theretainer straps 24 discussed above, each of the retainer straps 34 isprovided with an integral flange 34a. The flanges 34a extend acrossportions of the curved central portions of the retainer straps 34,defining a plane which is perpendicular to the plane defined by the endportions. When the cross 11 is assembled to the end yoke 31, two opposedbearing cups 12 are received in the recesses 32a and 33a, as shown inFIG. 4. The flanges 34a extend over one of the recessed areas 15 formedin the end surfaces 14 of the bearing cups 12. The flanges 34a engagethe one of the shoulders 15a formed on such end surfaces 14 so as toprevent rotation of the bearing cups 12 relative to the associated arms32 and 33 of the end yoke 31.

The embodiments described and illustrated thus far relate to universaljoint assemblies adapted for use with half round end yokes. However,this invention also relates to universal joint assemblies adapted foruse with full round end yokes. Referring now to FIGS. 5 and 6, there isillustrated a third embodiment of a universal joint assembly, indicatedgenerally at 40, in accordance with this invention. The assembly 40includes a conventional cross member 11 having bearing cups 12 mountedthereon, as described above in connection with FIGS. 1 and 2. Theassembly 40 further includes a full round end yoke 41. The end yoke 41includes a pair of arms (only one arm 42 is illustrated) havingcylindrical openings 42a formed therethrough A machined upper surface42b is formed about each of the openings 42a. When the cross 1i isassembled to the end yoke 41, two opposed bearing cups 12 are receivedin the openings 42a such that the recessed areas 15 lie in the sameplane as the machined surfaces 42b of the arms 42, as shown in FIGS. 5and 6.

Means are provided for retaining the bearing cups 12 within thecylindrical openings 42a of the end yoke 41. As shown in FIGS. 5 through7, such means includes a pair of retainer straps, indicated generally at43 (only one is illustrated). The retainer straps 43 extend over the endsurfaces 14 and the recessed areas 15 of the bearing cups 12. Each ofthe retainer straps 43 includes a central portion 43a connected bytransition portions 43b to end portions 43c. As best shown in FIGS. 6and 7, the end portions 43c lie in a plane which is offset from theplane defined by the central portion 43a. Thus, the transition portions43b define lower shoulders 43d between the central portion 43a and thetwo end portions 43c. Apertures 43e are formed through the end portions43c to permit threaded fasteners 44 to connect the retainer straps 43 tothe arm 42 of the end yoke 41.

When the cross 11 is assembled to the end yoke 41, two opposed bearingcups 12 are received in the openings 42a, as mentioned above. Then, theretainer straps 43 are secured to the arm 42 by the threaded fasteners44. When so secured, the lower surface of the central portion 43a liesacross the end surface 14 of the bearing cup 12, while the end portions43c lie across the recessed areas 15, as shown in FIG. 6. Also, thelower shoulders 43d of the retainer straps 43 engage the shoulders 15adefined on the end surface 14 of the bearing cup 12. Such engagementprevents rotation of the bearing cups 12 relative to the associated arms42 of the end yoke 41.

As shown in FIG. 7, the end portions 43c of the retainer strap 43 may beformed at an angle relative to the central portion 43a thereof. In otherwords, the planes defined by the end portions 43c are not parallel tothe plane defined by the central portion 43a. As a result, when theretainer strap 43 is secured to the arm 42 of the end yoke 41, the endportions 43c are flexed somewhat to the parallel position illustrated inFIG. 6. This flexing of the end portions 43a is useful in preloading thethreaded fasteners 44. The additional force which is required to flexthe end portions 43c causes the threaded fasteners 44 to additionallyengage the threads of the bores in the yoke arm 42 which they areengaged greater than if no force was required to flex the end portions43c. Because of this additional frictional engagement, the likelihood ofthe threaded fasteners 44 becoming loose during operation is reduced.

The angled formation of the end portions 43c is also helpful inaccommodating stack-up tolerances in the universal joint assembly 40.Such stack-up tolerances result when a number of components, each havingits own tolerance variations, are assembled together. In extremeinstances, the combined effect of the tolerance variations can causeundesirable looseness in the universal joint assembly 40. Thespring-like actions of the angled end portions 43c exert pressure on theend surfaces 14 of the bearing cups 12, urging them toward the crossmember 11. As a result, any looseness in the assembly 40 is eliminated.

Referring now to FIGS. 8 and 9, there is illustrated a fourth embodimentof a universal joint assembly, indicated generally at 50, in accordancewith this invention. The assembly 50 is generally similar to the thirdembodiment of the assembly 40 discussed above, except that the recessedareas 15 of the end surface 14 of the bearing cups 12 are not co-planarwith the machined surfaces 42b formed about the openings 42 of the arms42 of the full round end yoke 41. To accommodate this, a modifiedretainer strap, indicated generally at 51, is provided. The retainerstrap 51 includes a central portion 51a, a pair of intermediate portions51b, and a pair of end portions 51c. A first pair of shoulders 51d isdefined between the central portion 51 and the intermediate portions51b, while a second pair of shoulders 51e is defined between each of theintermediate portions 51b and the end portions 51c connected thereto.The first shoulders 51d engage the shoulders 15a on the bearing cups 12to prevent relative rotation, as described above. The second shoulders51e accommodate the different planes defined by the machined surfaces42b and the recessed areas 15.

The end portions 51c of the retainer straps 51 are secured to the arms42 of the yoke 41 by threaded fasteners 44, as described above. The endportions 51c of the retainer straps 51 may be formed at an anglerelative to the central portion 51a, as described above in connectionwith the retainer strap 43. Alternatively, a spring washer 52 may beused to preload the threaded fasteners 44 to prevent loosening thereof.The structure of one of the spring washers 52 is illustrated in FIG. 9.As shown therein, the spring washer 52 is formed having a slightlyarcuate shape when relaxed. When the threaded fasteners 44 aretightened, the spring washers 52 are flexed somewhat to the flatorientation illustrated in FIG. 9. This flexing exerts the preloadingforce on the threaded fasteners 44 similar to the manner describedabove.

Referring now to FIGS. 10 and 11, there is illustrated a fifthembodiment of a universal joint assembly, indicated generally at 60, inaccordance with this invention. The assembly 60 is generally similar tothe fourth embodiment of the assembly 50 discussed above, except thatthe retainer strap 51 has been replaced by a retainer clip, indicatedgenerally at 61. The retainer clip 61 includes a base portion 61aand anangled end portion 61b. The base portion 61a is secured to the arm 42 ofthe end yoke 41 by the threaded fastener 44. The angled end portion 61bextends over the recessed area 15 of the bearing cup 12. The edge of theend portion 61b engages the shoulder 15a. Because of its angledconfiguration, the retainer clip 61 functions in the same manner as theangled end portions 43c of the above-described retainer strap 43 toretain the threaded fastener 44 and to accommodate stack-up tolerancesin the assembly 60. The retainer clip 61 can also be used in combinationwith a half round end yoke.

Referring now to FIGS. 12 through 14, there is illustrated an alternatedesign for a retainer clip, indicated generally at 70, adapted for usein the fifth embodiment of the universal joint assembly 60 in lieu ofthe retainer clip 61. The retainer clip 70 includes a base portion 71, atransition portion 72, and an end portion 73. The base portion 71 has apair of openings 71a formed therethrough to permit it to be secured tothe arm 42 of the end yoke 41 by a pair of threaded fasteners (notshown). The end portion 73 extends over the recessed area 15 of thebearing cup 12. The edge of the end portion 73 is curved, unlike theabove-described retainer clip 61. Therefore, the edge of the end portion73 of the retainer clip 70 may, but does not necessarily, engage theshoulder 15a formed on the bearing cup 12. As shown in FIGS. 13 and 14,the thickness of the transition portion 72 varies between a maximum nearthe center thereof and a minimum adjacent to the openings 71a. Theretainer clip 70 functions in the same general manner as the retainerclip 61.

In accordance with the provisions of the patent statutes, the orprinciple and mode of operation of this invention have been explainedand illustrated in its preferred embodiment. However, it must beunderstood that this invention may be practiced otherwise than asspecifically explained and illustrated without departing from its spiritor scope.

What is claimed is:
 1. A universal joint assembly comprising:a yokeincluding an arm having an outer surface and an opening formedtherethrough extending inwardly from said outer surface; a cross havingan outwardly extending trunnion and an end; a bearing cup rotatablymounted on said end of said trunnion, said bearing cup including anouter circumferential surface and an end surface, said bearing cup beingdisposed within said yoke arm opening such that said end surface of saidbearing cup is located outwardly from said outer surface of said a ofsaid yoke; and a retainer clip including a base portion secured to saidouter surface of said arm of said yoke, an end portion extending over aportion of said end surface of said bearing cup to retain it within saidyoke arm opening, and a transition portion homogeneously formed betweensaid base portion and said end portion having a substantially uniformthickness, wherein lower surfaces of said base portion and said endportion define planes which are generally parallel and not co-planar,and wherein said transition portion defines a plane which extends at anangle relative to said planes defined by said base portion and said endportion.
 2. The universal joint defined in claim 1 wherein said bearingcup includes a recessed area formed in said end surface defining ashoulder, and wherein said end portion of said retainer clip terminatesin an edge extending into engagement with said shoulder defined on saidbearing cup end surface to prevent rotation of said bearing cup relativeto said yoke.
 3. The universal joint defined in claim 2 where said edgeof said retainer clip is curved.
 4. The universal joint defined in claim1 wherein said length of said transition portion includes a center andopposite ends, said center having a thickness greater than a thicknessof said ends.
 5. The universal joint defined in claim 4 wherein saidcenter of said transition portion has substantially the same thicknessas said base portion and said end portion.
 6. The universal jointdefined in claim 4 wherein at least one end of said transition portionhas a different thickness as said base portion and said end portion. 7.A universal joint assembly comprising:a yoke including an arm having anouter surface and an opening formed therethrough extending inwardly fromsaid outer surface; a cross having an outwardly extending trunnion andan end; a bearing cup rotatably mounted on said end of said trunnion,said bearing cup including an outer circumferential surface, an endsurface, and a recessed area formed in said end surface defining ashoulder, said bearing cup being disposed within said yoke arm openingsuch that said end surface of said bearing cup is located outwardly fromsaid outer surface of said arm of said yoke, said outer surface of saidarm of said yoke and said recessed area of said bearing cup definingplanes which are not co-planar; and a retainer clip including a baseportion secured to said outer surface of said arm of said yoke andextending over said surface thereof, an end portion extending over andengaging said recessed area of said bearing cup to retain it within saidyoke arm opening, and a transition portion homogeneously formed betweensaid base portion and said end portion having a substantially uniformthickness, wherein lower surfaces of said base portion and said endportion define planes which are generally parallel and not co-planar,and wherein transition portion defines a plane which extends at an anglerelative to said planes defined by said base portion and said endportion.
 8. The universal joint assembly defined in claim 7 wherein saidtransition portion includes a center of greater thickness than thethickness of at least one end of said length.